Apparatus for lapping and grinding balls



C- 24, w57 s. MESSERSCHMEDT g@ APPARATUS FOR LAFPING AND GRINDING BALLS Filed March ll, 1964 2 Sheets-Sheet l IN VENTOR.

ATTORNEYS.

Get. 24, 1967 s. MEssERsci-awasm 3,348,338

APPARATUS FOR LAPPING AND GRNDING BALLS 2 Sheets-Sheet 2 Filed March ll, 1964 ATTORNEW United States Patent 3,348,338 APPARATUS FUR LAPPHNG AND GRNDING BALLS Sebastian Messerschmidt, Altstadtstrasse 5,

Schweinfurt, Germany Filed Mar. l1, i964, Ser. No. 351,017 Claims priority, application Germany, Mar. 15, 1963,

3 Ciaims. (Ci. 51-3) The invention relates to the lapping and grinding of balls lbetween counteracting discs with concentric grooves guiding the balls, the balls being fed at each revolution in continuous succession to one side of a magazine and again removed at the other side thereof.

For rational production, modern apparatus for grindinf7 or .lapping balls, irrespectively of whether these operate with horizontal or vertical rotary lapping d-iscs, are tted with magazines which accommodate many more balls than can be taken between the discs. In these apparatus the balls, after being discharged from the lapping disc, are collected in the magazine and again fed therefrom to the lapping discs. For this purpose there are generally three types of magazines which come into quest-ion, namely a drum magazine, a bucket elevator and more recently a ring or annular magazine which rotates around the lapping discs.

Drum magazines do not separate the lapped, unlapped and more or less lapped balls, but mix these indiscriminately. The result is that the balls are worked unequally, because only the -balls having the largest diameter are actually lapped, whereas the others revolve idly with the discs. The unequal lball diameters result, however, in badly shaped grooves, which in turn impairs the work. The objections to the use of the bucket elevator as magazine differ only slightly from those inherent to the rotary drum, because the balls are here not fed without exception to a common stock in the magazine but are divided up into quantities corresponding to the number of buckets. However the mixing of the ground and unground balls cannot be avoided.

As compared therewith, the considerable advantage is obtained when using a yring magazine that the balls being worked move in practically the same sequence one after the other along the entire path of travel between the lapping discs and magazine. That is, a ground ball is only returned to the lapping discs when all the following balls have passed therethrough.

The use of a magazine in modern ball manufacture has, however, been found absolutely essential already on this account, because the lapping apparatus can be given a larger charge and the accuracy obtainable can be attributed precisely to this large number of balls. Moreover, in view of the comparatively slight lapping moment due to the rolling movement in the case of balls, this results in a more uniform stressing of the grooves in the lapping d-iscs, which must naturally have a favourable effect on the process of surfacing the balls.

The differences in diameter occurring when using drum and -bucket elevator magazines necessitates at least one sorting operation in separate sorting machines. To produce balls of greater precision in shape and size, the sorted classes are again subjected to a lapping process and subsequently sorted once more. This, however, adds considerably to the cost of production which increases proportionately with the precision obtained.

Being aware of the serious objections to the known processes for lapping and grinding balls, the object of the invention is to provide an apparatus which will produce balls with considerably less expenditure but with a very greatly improved degree of accuracy.

These advantages are attained according to the inven- ICC tion in that the balls in each groove or group of grooves are guided individually along an endless path of travel through the magazine and discs and at each revolution are transferred once in radial direction into the next following or preceding path of travel.

In this manner the individual balls pass through the working process in continuous succession from the grooves with the smallest radius to those with the largest radius on the discs, or in the reverse sequence. This regular guiding of the balls ensures exteremely uniform Working and results in equally regular lapping grooves, which in turn is to the advantage of the high degree of precision attainable by the process. As a result high precision balls with very narrow dimensional tolerances are produced so that no sorting operation is required and in addition the working time is reduced.

The invention also provides that the balls in the individual paths of travel are transferred at each delivery to or removal from the magazine. Which possibility is preferred will depend to a great extent upon the circumstances of the case in question. Thereby the balls of each groove or group of grooves are guided into the next following groove or group of grooves with the next larger or next smaller radius, whereas the balls in the outermost or innermost groove or group of grooves are fed into the lirst or last, that is the innermost or outermost groove or group of grooves, passing over all other paths of travel.

The construction of an apparatus provides that the magazine has a number of compartments corresponding to the number of grooves 'or groups of grooves in the discs and is connected at both sides to the aperture of the discs by means of guide paths subdivided in a similar manner.

As a result a number of separate endless paths of travel are produced for the balls which, with the exception of the path at the transfer point passing over the other paths of travel, extend parallel to each other. Thereby, in running through the magazine, substantially the same distribution is maintained as that provided by the grooves between the discs.

The invention assumes that it is known to remove the balls alternately from their path of travel Ibetween the discs and to reintroduce them into the machine in a dif- .ferent sequence or in different grinding grooves. For this purpose grooved paths of travel are provided Iwhich vform an extension of the aperture of the discs.

In further developing the general idea of the invention, another feature consists in that one of the outer tracks of yone guide path leads in known manner to the other outer side of the guide path passing over or under the other tracks in the process.

The balls passing out from between the discs one after another are moved forward in the guide paths -by the motion imparted to them between the discs. If necessary, however, special motive elements may also be provided, particularly at the places where the guide paths ascend.

A particularly advantageous embodiment of the invention consists in the employment of a plate-shaped magazine surrounding the discs in the form of a ring. Such a magazine can cooperate either with horizontally running discs or with vertically upright discs.

The plate can also be provided with a number of grooves corresponding to the grooves of the discs. On the other hand, however, it is also possible for the plate to have stationary concentrically arranged partition walls corresponding to the grooves or groups of grooves of the discs and forming an extension of the partition walls of the guide paths.

Whereas the embodiment with the magazine plate provided with grooves comes into question particularly for working balls of larger diameter, a magazine plate with partition walls between the individual paths of travel is aat-asas suitable chiefly for working balls of smaller diameter, in which case, however, it is advisable for several grooves to be assembled side by side on the discs and coordinated to a path of travel of the magazine subdivision.

Other features, details and advantages of the inventionl will bec-ome apparent from the following description of several embodiments of the invention illustrated by way of example in the accompanying drawings, in which:

FIG. 1 is a top plan view of the 1'irst embodiment,

FIG. 2 a section on line II-II of FIG. 1,

FIG. 3 a top plan view of a second embodiment,

FIG. 4 a part section of the embodiment of FIG. 3, and

FIG. 5 a part section through yet another embodiment.

In the forms of construction illustrated in FIGS. l to 4 a lapping disc arrangement provided with four rows of grooves is shown. This construction is, however, only an example which, as can be seen from FIG. 5, can be extended to discs with any desired number of grooves, but the diameter ofthe balls to be worked is the deciding factor. k

' In the apparatus shown in FIGS. l and 2 two concentrically arranged lapping discs are provided, the lower disc 1 of which rotates with its holder 2, while the upper disc 3 is stationary with its holder 4. While in the example illustrated the lower lapping disc 1 has four grooves 5 for guiding the balls 6, the upper lapping disc 3 has a fiat working surface 7. The upper stationary lapping disc 3 has a sector-shaped aperture 8 corresponding to an angle of 70'a as shown in FIG. l.

The two lapping discs 1 and 3 are arranged eccentrically within a ring-shaped plate magazine 9, the centres of the discs 1 and 3 on the one hand and of the ringshaped magazine 9 on the other hand being mutually displaced by an amount x on the diamater which forms the angle bisector of the aperture S of the upper lapping disc 3. The direction in which the lapping disc 1 rotates is indicated by the arrow 11. The ring-shaped magazine 9 rotates in the opposite direction as indicated by the arrow 12. The drives for the rotary lapping disc 1 and the ringshaped magazine 9 are not shown in detail as they are well known.

The ring-shaped magazine 9 is subdivided corresponding to the number of grooves of the lapping disc 1 into four paths of travel 13, 14, and 16, the path 13 having the smallest and the path 16 the largest radius. These paths 13 to 16 are formed by partition walls 17 which are supplemented by the outer wall 13 rotating with the ring-shaped magazine 9 and the stationary inner wall 19. The concentric partition walls 17 are also stationary and held by the supports 20. As can be seen from FIG. 2, the partition walls 17 terminate at a short distance from the bearing surface 21 of the magazine ring 9. The paths of travel 13 to 16 of the ring-shaped magazine 9 are connected at one end to one side of the aperture 8 in the upper disc 3 by guide paths designated as aY whole by 22 and at the other end to the other side of this aperture by guide paths designated as a whole by 23. The guide paths 22 and 23 are subdivided in a manner corresponding to the magazine 9 and the subdivision of grooves in the lapping disc 1. For this purpose the partition walls 17 are bent through an angle of 180 at their ends in a plane common with the ring-shaped magazine 9 and the lapping discs 1 and 3, so that in the case of the guide path 22 first three paths are formed which are designated by 24, 25 and 26. The path 24, which corresponds to the groove 5 of the lapping disc 1 having the largest radius, passes into the :path of travel 14 of the magazine 9 which is the second path, seen from inside. The path 25 corresponding to groove 5 of the lapping disc with the next smaller radius, leads into the path of travel 15 of the magazine 9 with the next larger radius and the next following path 26 finally leads into the outer path of travel 16 of the magazine 9 with the largest radius connecting it with the groove 5 of the lapping disc 1 second from the centre of the disc. The path 26 is bordered on the outer side by a stationary curved piece 27 which extends to the outer wall 18 of the magazine ring 9.

Coordinated to the groove 5 of the lapping disc 1 with the smallest radius is a groove 2S in the guide path 22 of U-shaped cross-section which ascends from its outlet point 29 in such a way that it finally crosses the paths 24 to 26 of the guide paths 22 before leading into the path of travel 13 of the magazine 9 which also has the smallest radius. Y

The guide path 23 is constructed like the guide path 22 at the other cross-over from the lapping discs 1, 3 to the magazine 9. VIn this case only the ends of the partition walls 17 are bent through an angle of 180 parallel to each other so that the individual tracks or paths 31, 32, 33 and 34 are formed and another curved piece 35 serves as boundary for the path 34 and is arranged stationary corresponding to the curved piece 27 on the other sidc so that it terminates in the proximity of the outer wall oi the ring magazine 9. The path of travel 13 of the maga zine 9 with the smallest radius passes over the guide path 31 to the groove of the lapping disc 1 with the largest radius. On the other hand the path of travel 16 of the magazine 9 with the largest radius passes over from the guide path 34 to the groove 5 of the lapping disc 1 with the smallest radius.

It the path along which the balls 36 travel is followed, it will be found that, taking into consideration the directions of movement 11 and 12 of the movable elements 1 and 9, the balls delivered by the groove 29 at 30 to the path of travel 13 of the magazine 9 are propelled by the movement of the magazine ring 9 and on reaching the end 37 of the inner boundary wall 19 of the magazine 9 they pass into the guide path 31 by which they are conducted to the groove 5 of the lapping disc 1 with the largest radius. In a similar manner these balls again leave the lapping discs in the region of the guide path 22, entering the guide path 24 thereof which leads to the path of travel 14 of the magazine 9 with the next largest radius as compared with the path of travel 13. The balls linally pass out from this path of travel 14 into the guide path 32 which conducts them to the groove 5 of the disc 1 with the second largest diameter. They leave this groove again via the guide path 25 which brings them to the next path of travel 15. This sequence of movement continues until the balls finally arrive in the groove 5 of the lapping disc 1 with the smallest radius. They pass out from this groove at 29 into the path 28 which transfers them into the path of travel 13 with the smallest radius. in being transferred the balls in the path or groove 28 pass over the balls in the three adjoining guides or paths 24 to 26. This sequence of movements continues until the balls 36 have been given the desired diameter and the necessary dimensional accuracy.

The embodiment illustrated in FIG. 3 corresponds in principle to that shown in FIGS. 1 and 2. However, in the lirst embodiment the balls in the magazine travel in clockwise direction and in the zone of the lapping discs in anticlockwise direction, whereas in the embodiment shown in FIG. 3 the direction of travel remains the same. To attain this the guide paths designated by '38 and 39 cross each other. The guide path 38 is formed by the parallel partition walls 40 which extend in a plane parallel to the ring magazine 9. The guides 41, 42, 43 and 44 are thus formed which conduct the balls, not shown, between the lapping discs 1 and 3.

The guide path 39 is composed of four parallel grooves 46, 47, 48 and 49 which commencing at the point 45 ascend as a whole and thereby cross the guide path 38. The groove or path 46 corresponding to the inner groove 5 of the lapping disc 1 leads to the second path of travel 14 of the magazine 9 seen from the inner side, while the guide or groove 49 of the guide 39 crosses the inner tracks 46, 47 and 48 and :at S0 leads into the path of travel 13 of the ring magazine 9 with the smallest diameter. In this manner the balls are always transferred to the next following path of travel on completing each revolution.

In the embodiment illustrated in FIG. 3 which corresponds to the section shown in FIG. 4, the concentric subdivisions of the ring magazine, instead of being formed by the partition walls 17 of the embodiment shown in FIGS. 1 and 2, are formed by grooves 51 the construction, arrangement and number of which corresponds to those of the grooves S in the lapping disc 1.

FIG. 5 shows diagrammatically a form of construction which is intended for working balls of smaller diameter. In this construction a separate path f travel is not provided on the guides 22, 23 or 38, 39 for each individual groove 52 of the lapping disc 53, but these grooves 52 are assembled in groups, the number of groups corresponding to the subdivision of the ring magazine which in this construction is subdivided into four paths of travel 13 to 16 in the manner shown in FIG. 1.

It is evident that the invention is not restricted to the embodiments described and illustrated in the drawings but that numerous modifications are possible without departing from the fundamental idea of the invention.

What I claim is:

1. Apparatus for lapping and grinding a plurality of balls comprising in combination:

a pair or" lapping Iand grinding discs concentrically located in opposed relation to each other, one of said discs having a plurality of concentrically arranged grooves therein;

means for rotating one of said discs;

magazine means including an annular rotatable base eccentrically arranged with respect to said discs, said magazine also including means dening a plurality of guiding channels for the balls to be ground and lapped, the number of channels being equal to the number of grooves in said disc;

means for rotating said base in a direction opposite to that of said one disc; said magazine including means for leading balls out of one groove on said disc, around one of said guiding channels, reinserting said balls in a different one of said grooves in sequential progression so that each ball travels the same path length around each groove between said discs and through the channels in said magazine and each ball traverses each of said grooves and channels in succession.

2. Apparatus as defined by claim 1 in which said means defining said guide channels in said magazine comprises a plurality of `annular concentrically arranged partitions stationarily disposed above and contiguous to said 15 base.

3. Apparatus as defined by claim 1 in which said means defining said guide channels in said magazine comprises a plurality of annular concentrically arranged grooves in the upper surface of said annular rotatable base. 2O

References Cited UNITED STATES PATENTS 947,249 1/1910 Lynch 51-130 949,912 2/1910 Rockwell 51-130 967,918 8/1910 Hirth 51-130 1,166,264 12/1915 'Schmidt 51-130 1,548,563 8/1925 Spencer 51-215 X 1,767,416 6/1930 Vuilleumier 51-130 1,772,365 8/1930 Pratt 51-130 2,766,556 10/ 1956 Messerschmidt 51--3 2,828,582 4/ 1958 Messerschmidt 51-3 FOREIGN PATENTS 8,541 4/ 1907 Great Britain.

LESTER M. SWINGLE, Primary Examiner. 

1. APPARATUS FOR LAPPING AND GRINDING A PLURALITY OF BALLS COMPRISING IN COMBINATION: A PAIR OF LAPPING AND GRINDING DISCS CONCENTRICALLY LOCATED IN OPPOSED RELATION TO EACH OTHER, ONE OF SAID DISC HAVING A PLURALITY OF CONCENTRICALLLY ARRANGED GROOVES THEREIN; MEANS FOR ROTATING ONE OF SAID DISCS; MAGAZINE MEANS INCLUDING AN ANNULAR ROTATABLE BASE ECCENTRICALLY ARRANGED WITH RESPECT TO SAID DISCS, SAID MAGAZINE ALSO INCLUDING MEANS DEFINING A PLURALITY OF GUIDING CHANNELS FOR THE BALLS TO BE GROUND AND LAPPED, THE NUMBER OF CHANNELS BEING EQUAL TO THE NUMBER OF GROOVES IN SAID DISC; MEANS FOR ROTATING SAID BASE IN A DIRECTION OPPOSITE TO THAT OF SAID ONE DISC; SAID MAGAZINE INCLUDING MEANS FOR LEADING BALLS OUT OF ONE GROOVE ON SAID DISC, AROUND ONE OF SAID GUIDING CHANNELS, REINSERTING SAID BALLS IN A DIFFERENT ONE OF SAID GROOVES IN SEQUENTIAL PROGRESSION SO THAT EACH BALL TRAVELS THE SAME PATH LENGTH AROUND EACH GROOVE BETWEEN SAID DISCS AND THROUGH THE CHANNELS IN SAID MAGAZINE AND EACH BALL TRAVERSE EACH OF SAID GROOVES AND CHANNELS IN SUCCESSION. 